fetchNext #

Fetches the next SearchResult, by triggering a new search/scroll request depending on the options and filters of the SearchResult.

If the previous request was a search or a scroll action which provided a scroll argument, fetchNext will use the scrollId retrieved from the current result to make a new scroll request.

If the previous request was a search action which provided size argument and sort filtering, fetchNext will use Elasticsearch's search_after mechanism, which can efficiently search through a large volume of documents, bypassing internal hard limits^[1], but at the cost of reflecting the latest changes of the index, as opposed to using scroll.

If the previous request was a search action which provided from and size arguments, fetchNext will add size to from and make a new search request.

How to process every document of a collection #

The safest way to process all documents in a collection is to fetch them as a batch in order to avoid memory exhaustion and possibly hitting some hard limits^[1] on the database layer.

Usage #

<?php
use \Kuzzle\SearchResult;
// ...
/**
  * @var $searchResult SearchResult
  */
try {
  $nextSearchResult = $searchResult->fetchNext();
} catch (ErrorException $e) {
  // Handle error
}

<?php
use \Kuzzle\Kuzzle;
use \Kuzzle\Document;
use \Kuzzle\Util\SearchResult;
function processDocument ($doc) {
  // do something with the document
}
$kuzzle = new Kuzzle('localhost');
$collection = $kuzzle->collection('collection', 'index');
try {
  $searchResult = $collection->search([
    'from' => 0,
    'size' => 1000,
    'scroll' => '30s',
    'filter' => []
  ]);
  while ($searchResult !== null) {
    foreach ($searchResult->getDocuments() as $doc) {
      procesDocument($doc);
    }
    $searchResult = $searchResult->fetchNext();
  }
}
catch (ErrorException $e) {
  // Handle errors here
}